Electrode assembly locating means



May 17, 1966 G. R. KAUTZ ET AL 3,252,032

ELECTRODE ASSEMBLY LOCATING MEANS Filed Dec. 13, 1965 2 Sheets-Sheet 1 INVENTORS George P. Kaufz & /an ZKury/a ATTORNEY y 1966 e. R. KAUTZ ET AL 3,252,032

ELECTRODE ASSEMBLY LOCATING MEANS Filed Dec. 13, 1963 2 Sheets-Sheet 2 VIIIIIII J 'fII/II).

INVENTORS G 7?. A 7 H1 5 BY 2755? w:

ATTORNEY United States Patent 3,252,032 ELECTRGDE ASSEMBLY LOCATING MEANS George R. Kautz, Seneca Fails, and Alan T. Kuryla, Geneva, N.Y., assignors to Sylvania Electric Products Inc., a corporation of Delaware Filed Dec. 13, 1963, Ser. No. 336,281 Claims. (Cl. 313-82) The invention relates to cathode ray tubes and more particularly to an improved structure for mating a plural electron gun assembly to a convergence magnetic pole piece assembly for use in a color cathode ray tube.

A conventional three-gun, three-color, shadow-mask type cathode ray tube as used in color television applications is comprised essentially of several related components enclosed within a hermetically sealed funnelshaped envelope having a light permeable face panel disposed oppoiste a tubular neck portion. A three-gun unitized electron beam source positioned within the tubular neck portion directs toward the face portion three related but individually controlled electron beams identified in the art as blue, green, and red beams, respectively. Oriented opposite the gun and ,in spaced relationship with the face panel is a metallic foraminous shadow mask through which the aforementioned electron beams are directed in a prescribed manner. The envelope face panel spaced back of the mask has thereon a multiplicity of three-dot triads of red, green, and blue phosphors disposed in a repetitive pattern of predetermined sequence to form a color screen for the visual display of desired information. Attached to the forward end of the unitized gun structure is a convergence magnetic pole piece assembly wherein the electron beams projected therethrough are positionally corrected to converge at the shadow mask to facilitate passage through an aperture of the mask and effect the desired beam landings on specific color dots of the adjacent screen. The magnetic fields for this gunmounted magnetic pole piece assembly are imparted thereto by associated convergence magnets exteriorly positioned proximal to the neck portion of the tube adjacent the interiorly oriented pole piece assembly.

The unitized electron gun structure comprises three individual guns of similar construction, each having an electron generating source or cathode, a control electrode, a focus electrode, and a high voltage beam accelerating electrode. These three electron guns are slightly tilted one with respect to-the other whereby, during operation, each of the three beams passes through its respective individual aperture in the magnetic pole piece assembly, through individual pairs of pole pieces, through the same aperture in the shadow mask, thence to simultaneously land on a specific color dot in the given triad. It can be seen from the foregoing discussion that a precise degree of alignment accuracy is required in properly mating the convergence magnetic pole piece assembly to the unitized electron gun structure.

Prior manufacturing techniques required individual assembly of both the magnetic pole piece unit and the unitized gun structure. These two component assemblies were then mated and aligned by a jigging operation wherein an alignment pin was temporarily inserted through each of the respective apertures in the pole piece unit and further extended into the gun structure to protrude through the aperture of a corresponding focus electrode. This procedure was difficult to perform satisfactorily since insertion of the pins into the gun electrodes easily disturbed the precise alignment of these electrodes. Furthermore, there was the inherent danger of physically distorting the several electrodes thereby imparting structural impairment detrimental to the intended operation. Thus, the degree of alignment achieved by this method left much to be desired.

Accordingly, it is an object of this invention to reduce the aforementioned disadvantages and to provide im- 3,252fi32 Patented May 17, 1966 proved positioning means for achieving efficient alignment of the unitized electron gun assembly with the magnetic pole piece assembly.

A further object is the provision of a simplified positioning means integral to the pole piece assembly.

A still further object is to provide means for electron gun-pole piece assembly alignment and jointure which leads to the production of an improved color cathode ray tube and to simplified construction methods.

The foregoing objects are achieved in one embodiment of the invention by the provision of affixing brackets on the base of the pole piece assembly adjacent the apertures therein to contact the peripheral terminal surface of each of the accelerating electrodes to facilitate jointure therewith and to provide positioning alignment of the electron guns with the respective apertures.

For a better understanding of the present invention, together with other and further objects, advantages, and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings in which:

FIGURE 1 is a sectioned plan view of a conventional multi-beam color cathode ray tube;

FIGURE 2 is a plan view of a typical convergence mag netic pole piece assembly taken along line 22 of FIG- URE 1;

FIGURE 3 is a view showing the base element of the magnetic pole piece assembly taken along line 3-3 of FIGURE 1;

FIGURE 4 is another view of the base element illustrating another embodiment of the invention;

FIGURE 5 is a partial sectioned view taken along lines 55 of FIGURE 4;

FIGURE 6 is a perspective view of the base element of the magnetic pole piece assembly showing another embodiment of the invention; and

FIGURES 7, 8, and 9 are partial sectioned views illustrating additional embodiments of the invention.

Referring to the drawings, there is shown in FIGURE 1 a conventional multi-beam color cathode ray tube 11 comprising a hermetically sealed envelope 13 containing a multi-gun electron mount assembly 15 from which issues a plurality of electron beams 17 directed to converge at an aperture 1h of the foraminous shadow mask 21. The beams 17 pass therethrough and diverge to land on specific color dots 23 comprising the cathodoluminescent screen 25 which is disposed on the interior surface of tube face panel 27.

The plural guns of the unitized mount structure 15 are suitably mated with the convergence magnetic pole piece assembly 29. Each individual gun of the unitized mount structure 15 comprises a first grid or G1 subassembly 31, a second grid or G2 electrode 33, a third grid or G3 electrode 35, and a cylindrical fourth high voltage accelerating electrode or G4 structure 37.

There is illustrated in FIGURE 2 a typical convergence magnetic pole piece assembly 29 comprising a disc-like base element 39 of nonmagnetic stainless steel having three discrete apertures 41 therein which must be maintained in concentric positional alignment with the respective high voltage accelerating electrodes (G4) 37. The base element 39 has integrally bonded to it a circular shell-like member 43 of nonmagnetic metal to which are attached pairs of spaced pole pieces 45 of magnetic metal which are positioned relative to the apertures 41 in axial and spatial alignment. Separating each pair of pole pieces are magnetic metal shields 47'designed to reduce the magnetic field interactions between the individual pairs of pole pieces 45.

As previously mentioned, the magnetic pole piece assembly 29 is mated to the multi-gun mount assembly 15 to provide axial alignment of the pole piece assembly apertures 41 with the respective accelerating electrodes 37 to thereby enhance the desired passage of the electron beams 17 during tube operation. operationally, the pole pieces 45 being of magnetic metal pick up lines of magnetic flux emanating from the externally positioned variable field strength magnets 4? and provide a low reluctance path for the lines of flux to be concentrated across the respective gaps 51 between the pairs of pole pieces 45. This concentrated field across each of the gaps 51 is utilized to correctively position the electron beams 17 passing therethrough to facilitate convergence of all beams at a shadow mask aperture 19. The emergence of the beams therethrough from the point of convergence results in the divergence of each beam to strike its specific color dot on screen 25.

To achieve the necessary mating alignment and jointure of the convergence magnetic pole piece assembly 29 with the associated multi-beam electron gun assembly 15, it has been found highly advantageous to incorporate jointure means in the form of a plurality of positioning integrators on the base element 39 of the pole piece assembly 29.

In this specification the term positioning integrator may be defined to encompass a bracket, tab, or rim that is formed with an upstanding surface suitable for both positioning and jointure or a well-defined perforation or slot that can be utilized for similar purposes.

A plurality of substantially L-shaped brackets 53 are shown in FIGURE 3 as being fixedly attached as by welding to base element 39 adjacent the apertures 41 at a locus 55 on a circumferential delineation 57 contiguous with the periphery of a respective cylindrical accelerating electrode 37.

The term circumferential delineation as used herein refers to a hypothetical circular line concentrically surrounding each aperture 41 on the base element 39 defining the circumferential outline of each electrode 37 mated thereto.

The upstanding portion 59 of the bracket 53 formsan extending member having a terminating edge which is oriented .to contact the cylindrical sidewall surface of an accelerating electrode 37 to provide concentric mating relationship of the electrode 37 with its respective apertures 41 and to facilitate jointure between the electrode and the base element of the magnet pole piece assembly. Pairs of brackets 53 are shown in FIGURE 3, but a great er or lesser number can be utilized in accordance with the concept ofthis invention.

Each integrator or bracket is disposed on the base ele- -ment 39 adjacent an aperture 41 at a locus 55 or 55 on either side of a radius 61 of the base element transversing the aperture. The locus being defined as the point where an extended aperture radius 63 or 63 intersects a circumferential delineation 57 contiguous with the periphery of 1 a respective electrode 37. The arcuate orientation of each locus is determined from the base element radius 61 by an acute angle A or A defined by the intersection of the associated aperture and base element radii.

It has been found that when utilizingone or more integrators for each electrode 37, the angles A and A can vary within a range of 0 to 80, and the angle for each integrator may be similar or may be different to adequately establish a specific support pattern for alignment and/or jointure. When employing a pair of integrators for each electrode 37, the angles of orientation A and A may preferably range from 10 to 80. Individual angles of have been found to be quite adequate to prevent movement of the electrodes.

Once the electrodes 37 are properly positioned by the upstanding portions 59 of the brackets 53, jointure as by welding may be made between the upstanding portions 59 and the continuous side wall of the electrode 37. There are occasions where the integrators or brackets 53 are used solely for positioning, the electrodes having one or more integral outstanding tabs or lugs 67 for jointure to the base element 39.

Although not shown, it is clearly evident that the brackets could be bonded to the base element to provide contact of the upstanding portions with the internal wall of the electrodes.

Another embodiment, as shown in FIGURES 4 and 5, provides a plurality of substantially upstanding integral tabs '71 resultant from discretely oriented punchings of the base element 39. These tabs are oriented relative to the circumferential delineations of the electrodes 37 as heretofore describe-d. As with the brackets 53, the upstanding tabs 71 are likewise formed as extending members with individually terminating edges and may be utilized for alignment and/ or jointure and may be oriented for contiguous contact with either the interior or exterior wall surface of the electrodes.

In another embodiment of the invention, as illustrated in FIGURE 6, a substantially upstanding rim 73 is integrally formed on the base element 39 to encircle the periphery of each enlarged aperture. The upstanding portion of each rim 73, which is formed as an extended memvided adequate means for concentric alignment of the aperture and the electrode and/ or jointure of the electrode to the base element.

Still another embodiment is shown in FIGURE 7 wherein the base element 39 has a plurality of perforations or integrators 75 discretely positioned on the base element adjacent the apertures 41 relative to the aforementioned circumferential delineation of the respective electrodes. In this instance each electrode has one or more integral tabs 77 extending longitudinally from the periphery of the terminal edge thereof as an extending member having an advanced terminating edge protruding in mating relationship with the perforations 75 in the base element to enter into and protrude therethrough thereby facilitating concentric alignment of the aperture and electrode. If desired, the electrode tab 77 may be bent to be contiguous with the inner surface of base element 39 to effect jointure between the electrode 37 and the base element.

The embodimentof the invention depicted in FIGURE 8 comprises a plurality of upstanding projecting members 79 integral to the base element 39 being formed as punchings similar to aforedescribed upstanding integral tabs 71. The projecting members 75*, being formed as extending members, each having a terminating edge, are oriented on a circumference larger than the circumferential delineation of the electrode to facilitate compatible mating with perforations 31 in an outstanding flange 83 extending from the periphery of the terminal edge of each electrode 37. In this manner another means is afforded for accomplishing concentric alignment between the electrodes and the apertures in the base element of the magnetic pole piece formed similarly to rim 73 which is an extending member having a terminating edge as described and shown in FIG- URE 6 except that rim 87 has a larger diametrical dimension to provide sliding engagement therein of the cylindrical end portion of accelerating electrode 37. This pro vides for concentric alignment of the aperture and the electrode and jointure of the electrode to the base element 39. In this embodiment means for seating the electrode 37 relative to the rim 87 may be facilitated by utilizing a stoppage formation on the electrode 37 such as an annular protuberance 89 on the electrode wall.

It is clearly evident that the herein described invention eifects an improved and simplified construction means for achieving efiicient alignment of the unitized electron gun assembly with the convergence magnetic pole piece assembly by providing positioning means integral to the pole piece assembly. Furthermore, the various embodiments '5 of the aforedescribed positioning integrators, in addition to providing alignment, also are of a form to effect jointure of the individual accelerating electrodes of the electron gun with the pole piece assembly.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

What is claimed is:

1. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related magnetic pole piece assembly, jointure means for aligning said electrodes with said apertures comprising:

a plurality of positioning integrators disposed relative to said base element and adjacent said apertures therein to provide concentric mating relationship of said apertures with said electrodes.

2. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal accelerating electrodes of a unitized gun structure are directed through corresponding circular apertures in the disc-like base element of a related magnetic pole piece assembly, jointure means for aligning said electrodes with said apertures comprisin a plurality of positioning integrators including means disposed on said base element to provide concentric matin relationship with said electrodes.

3. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal accelerating electrodes of a unitized gun structure are directed through corresponding circular apertures in the disc-like base element of a related magnetic pole piece assembly, jointure means for aligning said electrodes with said apertures comprising:

a plurality of positioning integrators including means disposed as pairs on said base element to provide concentric mating relationship of said apertures with said electrodes.

4. In a multi-beam color cathode ray tube wherein the electron bearns emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, jointure means for aligning said accelerating electrodes with said apertures comprising:

a plurality of substantially L-shaped positioning brackets spacedly afi'ixed in an upstanding manner on said base element adjacent said apertures to contact the sidewall surface of said electrodes facilitating jointure therewith and providing concentric mating relationship of said apertures with said electrodes.

5. In a multi-beam color cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a plurality of projecting integrators each having at least a portion thereof formed as an extending member with a terminating edge, said integrators elfecting discrete engagement between said base element and said electrodes to provide concentric mating relationship of said apertures with said electrodes.

6. In a multi-beam color cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a plurality of substantially L-shaped positioning brackets spacedly afi'ixed in an upstanding manner on said base element adjacent said apertures to contact the sidewall surface of said electrodes to provide concentric mating relationship of said apertures with said electrodes.

7. In a multi-beam color cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, jointure means for aligning said accelerating electrodes with said apertures comprising:

a plurality of substantially upstanding positioning tabs integral to said base element and adjacent said apertures to contact the sidewall surface of said electrodes facilitating jointure therewith and providing concentric mating relationship of said apertures with said electrodes.

8. In a multi-beam color cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a plurality of substantially upstanding positioning tabs integral to said base element and adjacent said apertures to contact the sidewall surface of said electrodes to provide concentric mating relationship of said apertures with said electrodes.

9. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disclike base element of a related convergence magnetic pole piece assembly, joint-ure means for aligning said accelerating electrodes with said apertures comprising:

a substantially upstanding positioning rim integral to each aperture of said base element and extending directionally toward each electrode, the upstanding portion of each rim being externally dimensioned to provide sliding engagement within the cylindrical end portion of a respective electrode to facilitate jointure therewith and to provide concentric mating relationship of said aperture with said electrode.

19. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disclike base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a substantially upstanding positioning rim integral to each aperture of said base element and extending directionally toward each electrode, the upstanding portion of each rim being externally dimensioned to provide sliding engagement within the cylindrical end portion of a respective electrode to provide concentric mating relationship of said aperture with said electrode. I

11. In a multi-beam cathode ray tube wherein the electron beams emanating vfrom individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, jointure means for aligning said accelerating electrodes with said apertures comprising:

a substantially upstanding positioning rim integral to each aperture of said base element and extending directionally toward each electrode, the upstanding portion of each rim being internally dimensioned to provide sliding engagement about the cylindrical end cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in i the disc-like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a plurality of positioning perforations disposed in said base element and adjacent said apertures, at least one perforation per aperture; and

a plurality of tabs longitudinally extending from the peripheries of the terminal edges of said electrodes, at least one tab per electrode, said tabs being formed for compatible protrusion through said perforations and being of a number equal to said perforations to provide concentric mating relationship of said apertures with said electrodes.

13. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the dis like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a substantially upstanding positioning rim extending from said base element to engage each of said elec trodes to provide concentric mating relationship of said apertures with said respective electrodes.

14. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in a disclike base element of a related convergence magnetic pole piece assembly, jointure means for aligning said accelerating electrodes with said apertures comprising:

a substantially upstanding positioning rim extending from said base element to engage each of said electrodes to effect jointure therebetween and provide concentric mating relationship of said apertures with said respective electrodes.

15. In a multi-beam cathode ray tube wherein the electron beams emanating from individual terminal cylindrical accelerating electrodes of a unitized gun structure are directed through corresponding apertures in the disc-like base element of a related convergence magnetic pole piece assembly, means for aligning said accelerating electrodes with said apertures comprising:

a plurality of projecting integrators each having at least a portion thereof formed as an extending member having a terminating edge, each of said members being disposed relative to said base element and said electrodes to ettect engagement therebetween and provide concentric mating relationship of said apertures with said electrodes.

References Cited by the Examiner UNITED STATES PATENTS JOHN W. HUCKERT, Primary Examiner.

DAVID J. GALVIN, Eramz'ner.

A. J. JAMES, Assistant Examiner. 

1. IN A MULTI-BEAM CATHODE RAY TUBE WHEREIN THE ELECTRON BEAMS EMANATING FROM INDIVIDUAL TERMIAL ACCELERATING ELECTRODES OF A UNITIZED GUN STRUCTURE ARE DIRECTED THROUGH CORRESPONDING APERTURES IN THE DISC-LIKE BASE ELEMENT OF A RELATED MAGNETIC POLE PIECE ASSEMBLY, JOINTURE MEANS FOR ALIGNING SAID ELECTRODES WITH SAID APERTURES COMPRISING: A PLURALITY OF POSITIONING INTEGRATORS DISPOSED RELATIVE TO SAID BASE ELEMENT AND ADJACENT SAID APERTURES THEREIN TO PROVIDE CONCENTRIC MATING RELATIONSHIP OF SAID APERTURES WITH SAID ELECTRODES. 